Single pass sorting of letter mail to carrier delivery order has long been a goal of postal automation. However, due to the difficulty of developing such a system in a form that is feasible in size, speed and cost, no practical single pass sorting system has yet been developed. Edmonds U.S. Patent Application 20030208298, Nov. 6, 2003, describes a method and system for single pass letter and flat processing including an induction and scanning system, a single pass sorting and packaging system for automatically sorting and packaging a plurality of mail pieces based on a single scan by the induction and sorting system, and a control unit connected to and controlling the induction and scanning system and the single pass sorting and packaging system. However, the disclosure of the Edmonds patent application is predominantly schematic in nature and does not provide a system for single pass sorting as proposed. Hanson U.S. Patent Application 20040065595, Apr. 8, 2004 to a single pass sequencer is likewise at a high level of generality, leaving the task of designing mechanical systems to accomplish the hoped-for results undescribed.
Pippin et al. U.S. Patent Application 20030038065, published Feb. 27, 2003 (the '065 application, now U.S. Pat. No. 7,138,596) and U.S. Patent Application 20020031284, Mar. 14, 2002 (now U.S. Pat. No. 6,715,614), the entire contents of which are incorporated herein by reference, describe an automated single pass mail sorting system wherein individual mail pieces are delivered and inserted into to slots by robotic delivery units. To accomplish this, the delivery units make use of H-belt inserters which are capable of inserting mail into a pocket in a vertical position, even where the pocket already contains some previously sorted mail. The pockets may contain bags such that each postal patron's mail is sorted into a bag at the end of a sorting run, and the bags as arranged on the sorting case are in delivery order.
The present invention provides a number of improvements to the sorting system of the foregoing Pippin et al. applications. First, instead of sorting directly to bags placed in the slots, a delivery point packaging machine is used to wrap the mail after sorting is concluded. For this purpose, the mail must be removed from the slots after sorting and transported to a wrapping station. This could be accomplished manually, but is preferably done by sorting the mail to a series of multi-slot pods mounting on the sorting case, and then removing the pods for extraction of the mail as described hereafter.
Commonly-owned Pippin et al. U.S. patent application Ser. No. 11/128,494, filed May 13, 2005 (now U.S. Pat. No. 7,426,996), the entire contents of which are incorporated by reference herein, describes a delivery point package for mail in the form of a folder that partially encloses the mail and has a pair of releasable contact adhesive stripes that allow the sides of the folder to cling to the outermost mail pieces on either side. This is a very desirable form of package that uses less packaging material than bags or polywrapping. The present invention addresses the problem of applying such a package as part of an automated single pass sorting process.